We propose to develop an ultraminiature implantable device which will measure both static and dynamic pressures and whose size and sensitivity indicate potential applications in the field of biomedical engineering. The heart of this device is an acousto-electric oscillator (AEO) which has the pertinent property of changing its frequency of operation proportional to the applied pressure. This device can measure dynamic or fluctuating pressures and has the capability of automatically distinguishing the frequencies involved and of measuring their individual intensities. One of the advantages of AEO, from the device point of view, is that its sole operational requirement is a small d.c. power supply such as a battery. Thus the device can be enclosed in a small self-sustaining package. Another important facet of the AEO is the fact that electrical connections are not mandatory. Since the oscillator operates on the radio-frequency range of electromagnetic waves, its radiation and thus pressure can be transmitted from point of origin and detected a few hundred yards from the oscillator with a suitable receiver. The pressure measuring device mentioned above is radically different in concept and use from the devices commercially available at the present time. This device has already been shown to be feasible in the investigator's laboratory. The proposal, therefore, is to extend this research to the stage where experimental models of this telemetering pressure measuring device could be made and field tested.